Switchable roller finger followers are known. See, for example, U.S. Pat. No. 7,174,869. Such finger followers have an outer lever pivotably mounted outside an inner lever and a roller rotatably mounted on a transverse axle in a slot in the inner lever. The top surface of the outer lever acts as a contact surface for a high lift cam and the top surface of the roller acts as a contact surface for a low lift cam. A coupling element is mounted at one end of the finger and oil from an oil source is used to activate the coupling element. When the coupling element is activated, it locks the outer lever to the inner lever and requires the follower to follow the high lift cam and transfer the lift to the valve stem of an associated intake or exhaust valve. When the coupling element is deactivated, the outer lever is free to pivot relative to the inner lever and, under the aid of a spring, the outer lever pivots freely in conjunction with the high lift cam while the motion of the low lift cam is transferred by the inner lever to the valve stem. This movement by the outer lever is conventionally referred to as the lost motion stroke.
Conventionally, the outer lever is a unitary structure such that the coupling element need only operate on one part of the outer lever. Typically, the coupling device operated on a yoke portion of the outer layer, the yoke portion being transverse to the longitudinal axis of the finger follower. Conventionally, the roller axle is staked to the inner lever to maintain its lateral position relative to the inner lever. U.S. Pat. No. 7,909,007 discloses a roller finger follower of this type. This provides a lost motion spring to maintain contact between the cam follower and the cam.
US2011/0197843 discloses the inventor's prior switchable roller finger follower in which the outer arm is formed by two separate outer arms that can move independently from one another and are connected to a common coupling element. However, the outer arms have a fairly complex configuration and associated cost. US2011/0197843 is incorporated herein by reference as if fully set forth.
It would be desirable to provide a finger follower of the type noted above with simpler manufacturing and reduced costs.